Sound-reproducing diaphragm



J. H. SUTL-JVE SOUND REPRODUCING DIAPHRAGM Filed Feb. 10, 1923 )4 TORNEY i Pat nted; ham 1925.

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' Application and February 10,1923. Serial No. 618,200.

To all whom it may concern:

Be it known that I, JAMES H. SUTLIVE, a citizen of the- United States,residing at Kansas City, in thecounty of Jackson and 5 State ofMissouri, have invented certain new and useful Improvements inSound-Repro-' ducing Diaphragms and I dodeclare the following to be afull, clear, and exact description of the invention, such as will enable10 others skilled in the art to'which itappertains'to make and use thesame, reference being had'to the accompanying drawings, and to thefigures of reference marked thereon, which forma part of thisspecification.

This invention relates to sound reproducing diaphragms and it isparticularly designed for use in connection with a mechanically operatedsound reproducing machine in which the diaphragm is operated by-avibratory arm toreproduce sound.

Heretofore diaphragms have been gen- 7 erally constructed ofvariousmaterials but theyhavev been more orlessinefficient due, I'believe, tothe fact that the whole dia phragm or the major portion of the diaphragmat least does not respond to the vibrations of the arm. The diaphragmsheretofore used have consisted of relatively stiff material withthe armfastened in the center; the result is that only a part of the diaphragmabout the center is vibrated so that the tones are more or less thin;that is, they are not rounded out with full resonance which has beenrecognized. as the desirable end sought by diaphragm manufacturers.

I have provided a diaphragm which, while of stiff material is soconstructed that it is flexible enough to permit bodily movement of themajor portion of the diaphragm so that a relatively large amount of airisdisplaced and so that the movement of the diaphragm is practically afull body movement as distinct from the fractional diaphragm movementcommon with diaphragms now in use. In actual practice I havedemonstrated that, as compared with present day diaphragms, a diaphragmconstructed-in accordance with my invention will produce a very markedresult and that when a comparison is made between the diaphragm formingthe subject matter of this invention and known makes of dia hragms, thetones resulting from the use 0 my diaphragm are broader and rounder, notnecessarily louder but with a of a very fiat cone having a straight endor 5 base and an inclined or cone face; there belng circumferentialgrooves on opposite faces .of the cone, the grooves on one face beingoffset with respect to those on the other so that the central solidportion of the diaphragm can have a free body move-- ment as distinctfrom a tilting or pivot movement common to present day dia phragms- In aformer application filed by me on or described a diaphragm which was ineifect cone-shaped but. it did not contain the grooves. I, therefore,intend that this application shall be a continuation in part of myformer application to obtain thebencfit ofthe filing date of the formerapplication for anything common in the two applications.

The invention will be better appreciated by reference to the followingdescription in connection with the accompanying drawings, in which Fig.1 is a sectional view through a sound box of a sound reproducing machineto which my invention is applied.

gig. 2 is a face view of the diaphragm, an

Fig. 3 is a cross sectional view on the line 33 of Fig. 2, the diaphragmbeing greatly magnified.

The diaphragm is shown as consisting of a flat cone preferably ofrubber. The base side 1 is the inside of the diaphragm and the cone side2 is the outside. The cone side is truncated,-that' is, the apex is cutoff to form a central disk portion 3, having an opening 4 to which-thestylus arm 5 may be secured. The diaphragm on the cone side merges fromthe edge of the central solid portion to the edge in an incline,providing a progressively uniform variable thickness, the thinnestportion being at the periphery of the disk within the outer ring and thethickest portion at the center.

On the respective sides or faces of the disk about June 17, 1920, SerialNo. 389,639 I are peripheral grooves 6 and 7 respectively, the grooves 6being ofl'set with respect to the grooves 7, as will be clearly seen inFig. 3. I prefer to {cut the grooves so that their floor portionswill berelatively flat and their outer 'wall'portions, for example,'at 8 and-9, at-substantially right angles tothe floor illustrated in thedrawings.

portionsto provide shoulders, the shoulders 8 and 9 being ofiset, as arethe grooves 6 and 7.

At the periphery of the disk is a sealing ring 10, within which is thethinnest portion of the disk, and it is fastened in the sound box 11 inthe usual way, the stylus arm be-- ing secured in the hole 4 by anysuitable means so that when the stylus 12 vibrates, a vibratory movementwill be imparted to the disk but instead of the central portion 3 onlyof. the disk vibrating, the entire inner portion, that is, the entirebody portion surrounding the ring 10 will have a movement back and forthin response to the vibrations due to the movement of the needle orstylus 12in the undulated grooves in the record.

The body movement of the disk within the ring portion 10 produces a verymarkedly superior tone over known types of diaphra-gms, the tone being.fuller and richer due, I believe, to the fact that more air is displacedon account of the body movement of the diaphragm caused by its peculiarconstruction. v I

I have illustrated what I consider the best form ofmy invention althoughI do not wish to be limited to the exact construction In actual practiceI have constructed the disk of hardTrtIbber and I find this admirablyserves as a material form which to construct the disk; the webconsisting of the corrugations made by the offset grooves and connectingthe solid central portion to the outer ring being quite flexible. I donot wish to be limited, however, to hard rubber in all instances becauseother materials might be used. y What I claim anddesire to secure byLetters-Paten't is:

1. A sound reproducing diaphragm consisting of a single piece in theformof a diskhaving a flat central portion of uniform cross section, theportion surrounding the v central portion having progressively de-'creasing cross section toward the periphery and a peripheral ring shapedportion integral with the second mentioned portion, the ring shapedportion being adapted to be clamped in position to. hold the diaphragmin place the portion of the disk immediately within the peripheral ringbeing the thinnest portion of the diaphragm so that all that portion ofthe diaphragm within the peripheral ring is adapted to move bodily withrespect to the peripheral ring.

2. A sound reproducin diaphragm con sisting of a disk having a atcentral portion of uniform cross section, the remaining portion of thedisk having a progressively decreasing cross section, the disk havingcircumferential rooves about its center on opposite faces, the floors ofthe grooves on opposite faces converging toward the periphery of thedisk.

3. A- sound'reproducing diaphragm conslstmg of a disk harm a centralportion of uniform cross section, t 1e remaining portion 1 of the diskhaving pro ressively decreasing cross section, the disk' ravingcircumferential grooves about its center, the Walls of the grooves beingformed with sharp angles and the grooves being on opposite sides of thedisk, those on one side being ofiset with respect to those on the otherside the floors of the grooves on opposite faces of the disk convergingtoward the periphery of the disk.

4. A sound reproducing diaphragm consisting of a disk having a centralport-ionofuniform cross section, the remaining portion of the diskhaving a progressively decreasing cross section toward theeriphery, thedisk vhaving circumferentia grooves about the central portion of uniformcross section, the grooves being on opposite sides of the disk andoffset with respect to one another, the grooves having flat floorportions, the outer Walls being at substantially right angles to thefloor portion, the floor portions merging ofi so that their inner edgeshave no walls. 1

In testimony whereof I afiix'm signature.

JAMES S TLIVE.

